Refrigerating machine oil composition and working fluid composition for refrigerating machine using same
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Solution Overview
Problem
Difluoromethane-based refrigerants are unstable and prone to degradation, leading to acid generation and corrosion in refrigeration systems, and existing refrigeration oils lack sufficient stability and lubricity to handle the high pressures and chemical instability of these refrigerants.
Innovation Solution
A refrigeration oil composition comprising a polymer obtained from monomers of monosubstituted and disubstituted ethylenes, combined with an ester of polyhydric alcohols and aliphatic monocarboxylic acids, providing improved miscibility, stability, and lubricity when used with difluoromethane-based mixed refrigerants.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If difluoromethane is used as a refrigerant, then lower GWP and environmental benefits are achieved, but the refrigerant degrades easily and generates acids that corrode system components
Solution Approach 1:
The patent introduces a specific refrigerating machine oil composition as an intermediary substance that interacts with difluoromethane to prevent its degradation. The oil composition including polymer (A) and ester (B) acts as a protective mediator that suppresses acid generation and prevents corrosion of system components, thereby resolving the contradiction between environmental benefits and chemical stability.
2Productivity
If difluoromethane is used under high pressure in the compressor, then refrigeration performance is improved, but wear and seizure easily occur due to thin oil film formation
Solution Approach 1:
The patent changes the chemical and physical parameters of the refrigerating machine oil by using a specific composition including polymer (A) with 75-100% of monomer (I) and ester (B) in a mass ratio of 5/95 to 45/55. This parameter change enables the oil to maintain adequate film thickness and lubricity under high-pressure compressor conditions, preventing wear and seizure while maintaining refrigeration performance.
3Ease of operation
If existing refrigeration oils are used with difluoromethane, then system operation is possible, but the oils lack sufficient stability and lubricity
Solution Approach 1:
The patent creates a composite refrigerating machine oil composition by combining polymer (A) and ester (B) in specific proportions. This composite material approach provides both the stability needed to resist difluoromethane degradation and the lubricity required for high-pressure compressor operation, while maintaining complete miscibility for system operability.
4Reliability
If a polyacrylic ester is used to improve lubricity, then compressor protection is enhanced, but miscibility and stability with difluoromethane-based refrigerants are insufficient
Solution Approach 1:
The patent applies local quality by using a specific type of polyacrylic ester (polymer A) with controlled monomer composition (75-100% of monomer I) and combining it with a specific ester (ester B). This localized optimization of the lubricant's chemical structure provides the right balance of lubricity for compressor protection and compatibility with difluoromethane-based refrigerants.
Data Source
AI summary
Provided is a refrigerating machine oil composition for a mixed refrigerant comprising difluoromethane, the composition comprising a polymer (A) below and an ester (B) of polyhydric alcohol(s) with aliphatic monocarboxylic acid(s).The polymer (A): a polymer which is obtained by polymerizing monomer(s) consisting of at least one monomer of monosubstituted ethylenes and disubstituted ethylenes, and in which a ratio of a monomer represented by the following general formula (I):wherein R1 represents an alkyl group having 1 to 14 carbon atoms, R2 represents hydrogen or an alkyl group having 1 to 4 carbon atoms, and the sum of carbon numbers in R1 and R2 is 2 to 14, is 75 to 100% by mass based on a total mass of monomers constituting the polymer.